Single triode with identical per-section electricals but completely different pinout — not a drop-in for a twin triode socket
Electrical Specifications
Absolute Maximum
Anode Voltage (max)Max Plate Voltage330V
Anode Dissipation (max)Max Plate Dissipation2.75W
Cathode Current (max)Max Cathode Current20mA
Heater-to-Cathode Voltage (max)Max Heater-Cathode Voltage100V
Max Grid Resistor
Notes
Originally designed for battery-operated equipment using a 12-cell storage battery, hence the 12.6V heater and the unusually low design-center plate voltage of 26.5V. The tube works fine at normal B+ voltages up to 300–330V.
The Tung-Sol datasheet rates Pa_max at 2.75W and Va_max at 330V, while the RCA datasheet rates Pa_max at 2.5W and Va_max at 300V. The higher Tung-Sol ratings reflect compliance with EIA standard RS-239.
Same ratings and characteristics per unit as the 6SN7GT (except heater: 12.6V/0.3A vs 6.3V/0.6A). The curves under types 6J5 and 6SN7-GT also apply to each unit of the 12SX7-GT.
Heater voltage variants: 12SX7/12SN7 use 12.6V/0.3A heater, 6SN7 uses 6.3V/0.6A heater. Same pinout and pin functions on all variants.
Pin Layout — Octal
1Control Grid (section 2)
2Plate (section 2)
3Cathode (section 2)
4
Socket-Compatible Tubes ⚠ Not electrically compatible